Macrocyclic Complexes Derived from 2,6‐Diformyl‐4‐X‐phenol: Substituent Effects and Phosphate Hydrolysis Activity

Abstract

Two 20‐membered macrocyclic complexes, [Cu2L1(ClO4)2] (1) and [Ni2L2(ClO4)2(H2O)2][Cu2L2(H2O)2](ClO4)2 (2) (where H2L1 and H2L2 are the condensation products of ɑ, ω‐amine with 3,3′‐((propane‐1,3‐diylbis(azanylylidene)) bis(methanylylidene))bis(5‐X‐2‐hydroxybenzaldehyde)), have been synthesized and characterized by X‐ray diffractions single crystal structure analysis. The results indicated that the structures of two complexes are symmetrical. In complex 1, the geometry around each copper(II) center is a slightly distorted square pyramidal with structural index parameter τ=0.062 for Cu1 and 0.067 for Cu2, the distance between Cu1 and Cu2 is 3.1075 Å. Complex 2 contains two similar macrocyclic units (A and B), the metal‐metal distances in A and B are 3.0760 and 3.0922 Å, respectively. The interaction between the complexes and calf thymus (CT‐DNA) were investigated by spectroscopic method. The phosphate hydrolysis activities of the complexes were examined using 4‐nitrophenyl phosphate disodium salt hexahydrate (pNPP) as the substrate. The corresponding catalytic rate constant (kcat) at pH 7.2 are 2.14×10−5 and 2.85×10−5 s−1, respectively, 104 times faster than the spontaneous hydrolysis of phosphate monoester.